Salvage from fish viscera



Patented A 20, 1946 SALVAGE FROM FISH VISCERA Ivan A. Partentiev, Nanuct, N. Y.

No Drawing.

Application November 25. 1943,

- Serial No. 511,704

This invention relates to the recovery of valuable materials from fish visceraand tissues.

More particularly, it relates to the separation of vitamins from these sources. k

This application is a continuation-in-part of my application Serial No. 448,648 filed June 26,

In the commercial processing of food fish tor the market, the entrails are usually discarded or, at best, are converted intb low-grade fish meal.

. With some of the larger fish such as certain types of the shark, the liver is utilized to recover oil containing vitamin A and little or no vitamin D, but the rest of the viscera is discarded. The methods for recovering the vitamin oil from the liver are usually cumbersome and costly. The

recla ms. (cue-11) days at 'l0-80 F. This approximates room temperatures in the .tropical regions where these op-. erations are most likely to be carried out. The

' temperature is then raised again to about 98F.

and after a short time. oil will be found to be separated as a surface layer.

After digestion, the large volume 011 forming the top layer andtransparent aqueous hydrolysate forming the lower layer may be sepadiscarded viscera or entrails not only contain I substantial quantities of vitamin A but are also good sources oi. vitamin D and some of the vitamin B components. I

It is one of the objects of the present invention to provide a simple and inexpensive method for the utilization of fish viscera and tissues as a valuable source of fat-soluble and water-soluble vitamins.

It is a further object to provide a method for the recovery of the vitamins from fish viscera and the like by means which will preserve such vitamins.

It is' a still further object to provide a meth for the treatment of fish viscera and the like which is suiiiciently simple to permit operation at the fisheries or on fishing boats and thereby to avoid shipment to special processing plants.

It is still another object to provide a process which can be applied to the separation 01' fats and water-soluble components from waste fish tissues containing the same.

These and other objects are attained by subjecting the raw viscera-and/or tissue, in an acidified aqueous medium, to the action of an acidacting enzyme at moderate temperatures. The process may be illustrated more specifically by the following examples.

Example 1 Fish liver is minced by means of a mechanical grinder and suificient hydrochloric acid is added to bring the mixture to an acidity of approximately pH 1.5-2.0. Hog pepsin or its proteolytic rated from the solid residue by decantation or siphoning 011. Oil or fat associated with the undigested residue may be recovered by a filtration operation in which the mixture oi fat and undigested residue on the filter is heated to about 37-40" C. (somewhat higher for some species of fish). With sufllciently complete digestion, the oil associated with the residue filters very easily through soft filter paper. During this filtration,

the undigested residue on the filter paper becomes relatively dry and this accelerates the separation of the oil from it. The filtrate, on standing, separates into two sharply defined layers with the oil floating on top of the watery solution. The oil is easily separated from the aqueous material by decantation or by the use of suitable separating devices based on the principle of a separatory funnel. The recovery of this oil by filtration through soft filter paper is a simple procedure which eliminates the necessity of adding alkali and thereby permits substantially complete recovery of oil without impairing the vitamin content. The several portions of oil and aqueous iractions'recovered as described, may be combined or may be handled separately. The

, oils are very transparent, of pale yellow color,

and form very little sediment on storage.

By the digestion of shark liver in accordance with the method described, a yield of oil was ob- 1 tained which represented about on the basis of the weight of the raw liver. The potency of this oil ranged from about 8000 to 10,000 I. U. 01" vitamin A per gram of oil. This is the same potency as is obtained commercially by the involved manuiact g processes commonly used. The liver oil obtained by the digestion process is very stable when digestion is carried out between pH 1.5 and 2.0. Several samples of such oil stored for a period of over 1 year without preservative, in white glass bottles, and opened a number of times, nevertheless showed no signs of becoming rancid. Tests carried out on the oil stored as just described, showed that the vitamin A content of the oil remained substantially constant during storage. One sample of oil, when bottled, had 8,962 I. U. oi vitamin A per gram and the same oil, stored in the white glass bottles, without preservative, still had 7,584 I. U. of vitamin A per gram after 6 months; The. potencies of oil set forth above were determined colorimetrically according to the Carr-Price method without saponiflcatlon.

The aqueous filtrate contains several vitamin B components. After digestion of four difierent samples of shark liver in-the same manner as Just described, it was found that one cc. of the clear filtrate or hydrolysate contained the following values of vitamin B crograms per cc.:

Riboflavin 2.56 2.86 Nicotinic acid 9.75 -13.3

Pantothenic acid 1.09 1.68 Biotin 0.163- 0.213

The aqueous hydrolysate may be concentrated to a small volume or may be dried to a powder.

A dry, powder obtained from tuna fish liver by the described method contained, per gram of powder, the following vitamin B values:

as expressed in mi- Micrograms per cc.

1 Pantothenic acid 186.2

-Nlcotinic acid 41.3

Micrograms Riboflavin 150 Pantothenic acid 12.7 Nicotinic acid 37.5"

While the oil obtained as just described is generally clear, it has a tendency to become slight y cloudy, especially on cooling. .When the oil is cooled to about 32 K, it solidifies as an opa mass. However, I have found that the oil may be further purified by treating it with solid masnesium lactate in the proportion of about 1 to 10% by weight. based on the weight of the oil to be treated. More specifically, as illustrative. I'may add 5% of the magnesium lactate powder to the oil after it has been separated by decanf tation or otherwise as described. The mixture is then agitated by shaking, stirring, or the like,

iwfor a short period of time and the magnesium i lactate powder is removed from the oil by filtration. The oil is then found to be brilliantly 1.

Dale yellow in color and to have but slight odor..

This method may also be used on liver of other types of mu than shark. e. g., tuna, halibut, cod. 1 bluefish, mackerel, etc. Other organs than the 1 liver may be treated in substantially the same manner to obtain compositions containing vita- 1 mins as well as other fat-soluble components such as hormones. The viscera and livers of many small fish are impractical as sources of vitamins in the usual processes for recovery of the same 1 but, by utilizing the present method, these organs and tissues may be treated efi'ectively and 75 state. Alternatively, the pasty material may be g was ground in a meat chopper, diluted with wa-' 4 efiiciently. Furthermore, the muscle tissues'of certain species of fish, such as eels, are rich in vitamin B and the like and by utilizing the present method, it is possible to recover such vitamins.

Example 2 Two thousand parts of old, salted tuna fish liver ter to about 20,000 parts and the mixture was .adjusted to pH 1.5 by the addition of concen trate'd hydrochloric acid.] Seven parts of pepsin dissolved in a smallamount of water was added and digestion was carried on for two days at a temperature of about 37 C. At the end of this period some oil had' separated and floated on the top of the aqueous liquid and was recovered by decantation as in Example 1. The fatty substances assoclated with the undigested solid residue, were separated by filtering the mixture at rooin temperature. During the filtration, some of the oily material solidified but was melted again by heating to about 37 C. About 400 parts of crude fat were obtained. The pure oil was eas y extracted from the crude fat by mixing the latby decantation or filtration. The ether was evapter with an equal or double amount of ether. the ether solution being separated from the residue orated and the yield of the oil indicated that'at least of the crude mt was oil, or about 10% by weight of oil based on the weight of the original salted liver. The extracted oil contained about 118,480 vitamin A units in each gram. The vitamin content of the oil obtained by the digestion method agreed very closely with that found in oil obtained by extraction methods, thus indicating that the digestion step did not cause any substantial loss of vitamin.

The aqueous filtrate or hydrolysate obtained in separating the crude fat in the first filtration was '40 found to contain the following values of vitamin This oil remains clear on standing and, while it' solidifies at low temperatures, when the tempera- 1 ture is raised the solid melts to form the clear Y oil.

B comp nents as expressed in micrograms per 1 On the basis of the original liver, these vitamin B components were present in the following amounts as expressed in milligrams per kilogram of liver:

Riboflavin 140 Nicotlnic acid 31 Pantothenic acid 14 Biotin 0.8

Example 3 v Fish entrails, obtained from the commerci fish-dressing process, were ground in a meat chop-- per and enough hydrochloric acid was added to bring the pH to about 1.8. In order to speed the digestion. one gram of pig pepsin was added for ev y t r of entrails. Digestion was carried on at 37 C. for 1-3 days. At the end of i P od. the fat and associated undigested residue were separated by filtration from th tery filtrate.

The acidity of the watery filtrate obtained after digestion of the entrails was adjusted to pH 3 to prevent acid corrosion in drying. It was then concentrated about 20 times ina vacuum dessicator until it turned to a semi-solid paste. This pasty material was dried to powder by freezing and then drying under vacuum while in the frozenplaced in suitable trays in a drying oven or the like and the dry product there obtained may be ground to powder. The fish meal thus obtained contained about 12% nitrogen and represented about 8-10% of the weight of raw entrails; One gram of the fish meal obtained from mackerel entrails contained 16.1 micrograms riboflavin, 80.5

micrograms pantothenic acid and 140 micrograms nlcotinic acid. Fish mealsimilarly obtained from thenic acid, and 97.0 micrograms nicotinic acid.

Instead of concentrating the watery filtrate as described, I may mix tricalcium phosphate with such filtrate in greater or lesser amounts. The phosphate will adsorb most of the vitamin-containing materials and may be separated from the water. By using larger amounts of the phosphate, a pasty mass may beformed which quickly and easily dries to a powder. Since the tricalcium phosphate is a desirable constituent for poult y foods and the like, its use in this connection serves the double function of concentration or drying and as a constituent of thepoultry food. Similarly, absorbent silica or other absorbent materials may be used in place in the calcium phosphate.

The fat associated with the residue from the digestion of the entrails contains a considerable proportion of vitamins A and D and may be recovered as described by heating the residue and ,filtering it, .while' warm, through soft filter paper based on theweight of the raw materials. This I oil varied from about 3,000 .to about 13,000 U. S. P.

units vitamin A per gram of oil.

The oil may be mixed with more or less of the meals obtained from the watery filtrate described to give a better product for chicken feed or the like. Alternatively, the oil may be mixed with the watery filtrate before it is dried or in one of the intermediate stages of drying.

In place of hog pepsin described in the specific examples, it is frequently more convenient to use the fish stomach juice and/or the ground stomach tissue secreting or containing pepsin, available at the fisheries. Of course, equivalent amounts of the fish pepsin are used in place of the hog pepsin. When entrails are used, they usually contain sufficient pepsin for the digestion but more may be added if necessary or desirable. Other proteolytic enzymes which are active under acid conditions may be substituted but, for most purposes, pepsin is more readilyavailable. The acidity of the mixture during the digestion period may vary somewhat from pH 1.5 to about pH 5.0. It is desirable that a low pH be maintained during the digestion process in order to prevent bacterialaction and to prevent rancidity. A pH of 1.5-2.0

represents an optimum condition for the temperatures employed. Where the pH is less acid than about 3.0 it is preferable to add an antiseptic.

Q The acidification of the liver suspension is favpreservatives.

It should be noted that the bulk of the digestion takes place at the comparatively low' temperatures not exceeding about F. By processing the viscera or the like at such low temperatures, higher yields of vitamins are obtained, since elevated temperatures tend to, decompose the vitamins. The temperatures of 70-80 F. are approximately equivalent to room temperatures in many of thos sections where the fisheries are located and hence, by the present process, the major portion of the operation may be carried out at or not greatly above room temperatures. Naturally, this simplifies the procedure and apparatus required and is obviously highly desirable from a commercial standpoint. 'More specifically, there is provided a simple and inexpensive method for obtaining high-grade oil and other vitamin .products at the fisheries on a large scale and in good yield. These processes are especially valuable since they salvage abundantwaste materials. 1

The enzyme digestion process utilized herein potency. No preservatives are necessarycwith the oil obtained in accordance with the present invention. -The liver oils of commerce, previously available, were of such composition that it was found necessary to store them in amber-colored or opaque containers. Even then, such oils tended to become rancid and to lose their vitamin potency so that many substances have been suggested for use as preservatives. These precautions are not necessary with oils obtained a described herein. Another advantage of the oil obtained by the digestion method is that the oil contains practically no free fatty acid.

Nutritionally, liver and other visce'ra proteins rank high as a source of essential amino'acids. The solids recovered from the aqueous solution resulting from the digestion of fish livers are, therefore, not only a source for the vitamin B factors but they also contain substantially allthe nutritionally essential amino acids originally present as constituents of the viscera proteins.

While some of the aqueous filtrates obtained from the digestion process as described above may be rather dilute as regards solids content, they may be concentrated in any known manner where due precaution is taken to avoid decomposition of the vitamin components of the solution. Vacuum concentration at low temperatures is efiective and, for certain purposes, spray drying is especially convenient. Where the vitamin B conparting from the spirit and scopethereof as defined in the appended claims.

Iclalm: r

1. The proces which comprises preparing an aqueous suspension of comminuted fish viscera at about pH 1.5, adding a small amount of pepsin to the suspension, maintaining the suspension at temperaturesbetween about 70-100 F. until the oil separates and floats to the surface, removing the acid liquid from the solid residue and sepa-- rately recovering the oil and a vitamin B-containing aqueous solution from the acid liquid.

2. A process of recovering vitamin-containing materials which comprises subjecting fish viscera in an aqueoussuspension to the digestive action of pepsin at a pH oi! about l.5 and at temperatures notsubstantially exceeding about 100 F.

until oil separates from the aqueous suspension, and separately recovering from the acid digestion product the vitamin-containing oil and the vita-.

min-containing aqueous solution.

' 3. A process of recovering vitamin-containing materials which comprises subjecting comminuted fish viscera in an aqueous suspension to the digestive action of pepsin at about pH 1.5

- and at temperatures not substantially exceeding about 100 F. for about two dayaseparating the acid liquid material from the solid residue, turther separating the acid liquid material into an oily fraction and an aqueous fraction anddrying the aqueous traction. p 1

4. A process of recovering vitamin-containing materials which comprises subjecting comminutedfish viscera in an aqueous suspension to the digestive action of pepsin at about pH 1.5 and at temperatures not substantially exceeding aboutlOO" F. for about two days, removing the acid liquid from the solid residue and separately recovering vitamin-containing oil and vitamin-- containing aqueous solution from the liquid. v

5. A process of recovering vitamin-containing materials which comprises subjecting comminuted fish viscera in an aqueous suspension to the digestive action of pepsin at about pH 1.5 and at temperatures not substantially exceeding about 1009 1". for about two days, adding alkali to adjust the pH to about 3, removing theliquid a concentrating treatment to recover a concentrated vitamin product.

10. A concentrated vitamin-B containing product' containing water soluble vitamins oi fish viscera and water soluble peptic-digestion products of fish viscera, including acid salts of protein digestion products.

11. A dry vitamm-B containing product containing in a concentrated form water soluble vitamins of fishviscera and soluble peptic digestion products of fish viscera, including acidv salts of protein digestion products Y 12. A process of recovering both vitamin-containing' oils and water soluble vitamins from fish entrails containing pepsin whichcomprises adding acid and subjecting the entrails to digestion with their contained pepsin under acid conditions and without further addition pepsin and subjecting the still acid digestion product to a separation treatment to separate vitamin-contaimingv oil and an acid aqueous vitamin-cong extract therefrom, which aqueous extract-contains water soluble vitamins and other water soluble digestion products of the entrails including such constituents in the form of their acid salts;

13. The process of recovering both vitamincontaining oils and water-soluble vitamins from fish viscera which comprises subjecting fish viscera to the digestive action oi-pepsin under acid conditions and subjecting the still acid digestion product to a separation treatment to remove vitamin-containing oil and an acid aqueous vitaminfrom the solid undigested residue, separately recovering vitamin-containing oil and vitamincOntaining aqueous solution from the liquid,

- not to a separation treatment toseparate vitamin-containing oiltherefrom.

7. A process of recoveringvitamin-containing materials which comprises subjecting comminuted fish viscera. in an equeous'suspension to the digestive action of pepsin at a pH oi about 1.5, increasing the pH to about 3 after such digestion, and subjecting the still acid digestion prodnot to a separation treatment to separate vitamin-containing oil and an acid aqueous -1- itamincontainingextract therefrom.

8. A process of recovering both vitamin-coming oils and water soluble vitamins from fish viscera which comprises subjecting comminuted fish .viscera to the digestive action of pepsin at a pH of about 1.5 and subjecting the resulting still acid digestion product .to aseparation treatment to remove vitamimconta'ining oii and a vitamincontaining aqueous solution.

I 9. The process according to the preceding blaim inwhich the acid aqueous solution is subjected to containing extract thereirom, which aqueous ex tract contains water soluble vitamins and other water soluble digestion products of the entrails I including such constituents in the form '0! their acid salts.

14. The process of recovering both vitamincontaining oils and water-soluble vitamins irorn fish viscera which comprises'subjecting fish viscera-to the'digestive action of pepsin under acid conditions 'and subjecting the still acid digestion product to a separation treatment to remove vitamin-containing oil and an acid aqueous vitamin containing extract therefrom, which aqueous ex:

tract contains water soluble vitamins and other water soluble digestion products of the entrails including such constituents in the form of their acid salts and said separation treatment including a filtration separation of oil from the 'warm residue after the separation of the aqueous. solution therefrom.

15. The method or recovering vitamin-containing materials from fish viscera which comprises subjecting comminuted fish'viscera in an aqueous suspension to the digestive action 01 pepsin under acid conditions and at a temperature below that of substantial decomposition of the vitamins, removing the aqueous liquid-from the solid residue and subjecting the solid residue. with admixed oilto filtration after partial drying and at a temperature at whch the oil is liquid to facilitate separation of oil from the solid residue.

16. A concentrated vitamin'B-containing product resulting from the peptic digestion of fish jvis'cera under acid conditions, said product being" T substantially free from oil andfrom waterinsoluble products of digestion and containing water soluble vitamins of fish viscera and .water soluble protein digestion productsof fish viscera including such products in the form ofhydrochlorides.

PARFENI'JEV." 

